Air pollution studies in the city of Zagreb II. concentrations of sulphur dioxide and smok

Izvršena je analiza rezultata jednogodišnjeg mjerenja dnevnih koncentracija S02 i dima u atmosferi Zagreba na 4 mjerna mjesta. Nađene su vrlo velike razlike u koncentraciji sumpornog dioksida između ljeta i zime, a to pokazuje da su glavni izvori onečišćenja atmosfere kućna ognjišta. Koncentracije dima pokazuju sličan .godišnji tok, ali s manjim ekstremima. Koncentracije S02 zimi daleko premašuju čak i blaže higijenske standarde, a naročito su visoke u gusto naseljenim stambenim dijelovima grada. Preporučene su mjere za asanaciju.A one-year survey of daily S02 and smoke concentrations in air was carried out at four sampling points in Zagreb by means of a »volumetric apparatus«. Considerable differences were found between summer and winter S02 concentrations, especially in densely populated areas, which shows chat the air pollution was mainly caused by domestic heating. Smoke concentrations expressed in COH-units had a similar yearly trend but with less expressed extremes. Weight concentrations of suspended particles estimated from the optical density by three different calibration curves (for winter, summer, and intermediate seasons) showed no significant seasonal variations. In the course of the three widest months (December, January, February) the level of 500 µg S02/m3, used in some western countries as the maximum permissible level, was permanently surpassed in the densely populated area and for about a third of the clays in other parts of the town. The maximum value (4,870 µg SO2/m3) found in the period of heavy air pollution in January exceeded the maximum values found during London fog in 1952. It is suggested that district heaving should be introduced at least in the parts of the town to be built in the future